BEL BM-A1, User Manual

Page 1: ...BM A1 Audio monitor alarm system User s Guide Version 0 2 05 02 04 ...

Page 2: ...t which is nevertheless supplied for information purposes only and does not constitute any form of warranty or guarantee All trademarks acknowledged The information in this document is subject to change without notice Bel Digital Audio Ltd Unit 3 Horwood Court Bletchley Milton Keynes Bucks MK11RD Tel 01908 641063 Email info beldigital com Web www beldigital com ...

Page 3: ...NNECTOR I O 6 Alarms connector pinout 6 RS232 Host interface connector pinout 7 CONFIGURATION 8 Adjusting analog input level 9 Adjusting audio monitor output level 10 Adjusting bargraph break points and ballistics 11 Inserting bargraph graticules 14 BM A1 SERIAL PROTOCOL 15 OVERVIEW 15 Frame format 15 COMMANDS 16 DATA FORMATS 17 PROBLEM SOLVING 21 Sample problems and their solutions 22 SPECIFICATI...

Page 4: ...r audio over level audio loss and anti phase Main features 2 x AES and 2 x analog audio input pairs Option for balanced XLR or unbalanced BNC digital audio I O High quality high SPL audio reproduction with bass speaker and soft limiting 4 x tri color bargraphs with six standard scales and ballistics adjustable color transition points and peak hold facility Alarms for audio AES loss over level and ...

Page 5: ...tors The left and right speaker switches select which of the currently selected audio channels is available at the speakers after three stages of analog processing The selected audio is first passed through factory preset equalization filters Then electronic level control is applied with the balance and volume knobs providing control voltages Soft limiters are used to protect the speakers The head...

Page 6: ...rrently selected four audio channels are monitored for persistent under level An alarm is generated when an input is 30dB 50dB for AES meter for more than 15 seconds Bottom bargraph segment flashes amber Audio tone TTL serial o p Audio over level The currently selected four audio channels are monitored for transient over level An alarm is generated immediately when the first red segment of the rel...

Page 7: ... to monitor only the active inputs The SET function can be disabled using a serial command If alarms are present moving the toggle switch to the center position will stop the audible alarm but retain the visual alarm indications and TTL serial alarm outputs The switch must be held in the ALARM RESET position for more than 3 seconds for all alarms to be cleared The center position is the recommende...

Page 8: ...0dB 300mSec 300mSec BBC PPM 12 to 12dB mark 7 to 1 10mSec 2 85Sec mark 7 to 1 VU EXT 80dB 20 to 60dB 300mSec 300mSec NORDIC 54dB 12 to 42dB 5mSec 1 7Sec per 20dB decay BM A1 scale ballistics Stick on scale graticules which may be applied to the space between the front panel bargraphs are supplied with the unit BM A1 scale graticules Note Bargraph color transition points and peak hold decay may als...

Page 9: ...gh these vents is not impeded Connector I O All connections with the exception of the headphone socket are provided on the rear panel of the frame All data connectors use 9 way D type connectors The BM A1balanced audio version rear view Digital audio I O may be supported with either XLR connectors for balanced audio or BNCs for unbalanced audio depending on the BM A1version specified at the time o...

Page 10: ...onnector pinout Connector type 9 way D female Speed 9600 bps Format 8 bit no parity 2 stop bits Pin Description 1 Not connected 2 Rx from host 3 Tx to host 4 Not connected 5 GND 6 Not connected 7 Not connected 8 Not connected 9 Not connected Note A null modem lead will be required to interface to a PC ...

Page 11: ...adjustments The following adjustments may be made Monitor output level SW3 potentiometers main board RV1 RV2 Analog input level SW4 and SW5 potentiometers RV3 4 5 6 main board Bargraph settings SW2 and SW6 main board near power supply Warning Configuration instructions are for trained personnel To avoid dangerous electric shock do not remove any covers or carry out adjustments unless qualified to ...

Page 12: ...5 2 0 dB 0dBu in 0 on analog scale 6 2 4 dB 4dBu in 0 on analog scale 7 2 8 dB 8dBu in 0 on analog scale 8 2 Variable adjacent pot 10 to 12 dB SW5 Anlg Input Setting when ON 1 3 0 dB 0dBu in 0 on analog scale 2 3 4 dB 4dBu in 0 on analog scale 3 3 8 dB 8dBu in 0 on analog scale 4 3 Variable adjacent pot 10 to 12 dB 5 4 0 dB 0dBu in 0 on analog scale 6 4 4 dB 4dBu in 0 on analog scale 7 4 8 dB 8dBu...

Page 13: ...B 0 on analog scale 0dBu on output 2 Left 4 dB 0 on analog scale 4dBu on output 3 Left 8 dB 0 on analog scale 8dBu on output 4 Left Variable adjacent pot 0 to 12 dB 5 Right 0 dB 0 on analog scale 0dBu on output 6 Right 4 dB 0 on analog scale 4dBu on output 7 Right 8 dB 0 on analog scale 8dBu on output 8 Right Variable adjacent pot 0 to 12 dB Note It is intended that only one switch lever is set to...

Page 14: ...ls Note When digital inputs are used with an analogue scale the analogue outputs will be less than that indicated on the meters since the digital to analogue converters clip at 15 dB The effective loss is 3dB when the 18 dB position is selected and 5dB when the 20 dB position is selected SW2 7 SW2 6 Peak hold decay OFF OFF None Off OFF ON 3 seconds ON OFF 7 seconds ON ON Indefinite SW2 5 SW2 4 SW2...

Page 15: ...llows SW2 2 SW2 1 SW6 8 SW6 7 SW6 6 Segment from bargraph top OFF OFF OFF OFF OFF None OFF OFF OFF OFF ON 1 OFF OFF OFF ON OFF 2 OFF OFF OFF ON ON 3 OFF OFF ON OFF OFF 4 OFF OFF ON OFF ON 5 OFF OFF ON ON OFF 6 OFF OFF ON ON ON 7 OFF ON OFF OFF OFF 8 OFF ON OFF OFF ON 9 OFF ON OFF ON OFF 10 OFF ON OFF ON ON 11 OFF ON ON OFF OFF 12 OFF ON ON OFF ON 13 OFF ON ON ON OFF 14 OFF ON ON ON ON 15 ON OFF OF...

Page 16: ...FF OFF 4 OFF OFF ON OFF ON 5 OFF OFF ON ON OFF 6 OFF OFF ON ON ON 7 OFF ON OFF OFF OFF 8 OFF ON OFF OFF ON 9 OFF ON OFF ON OFF 10 OFF ON OFF ON ON 11 OFF ON ON OFF OFF 12 OFF ON ON OFF ON 13 OFF ON ON ON OFF 14 OFF ON ON ON ON 15 ON OFF OFF OFF OFF 16 ON OFF OFF OFF ON 17 ON OFF OFF ON OFF 18 ON OFF OFF ON ON 19 ON OFF ON OFF OFF 20 ON OFF ON OFF ON 21 ON OFF ON ON OFF 22 ON OFF ON ON ON 23 ON ON ...

Page 17: ...each BM A1 BM A1 scale graticules To apply a graticule proceed as follows peel back the protective backing from the chosen graticule apply the graticule to the space between a pair of bargraphs repeat the process for the other bargraph graticule position ensure that the bargraph setting matches the graticule adjust the color transitions and peak hold decay as desired ...

Page 18: ...ion Any requested reply then follows in the same frame format Frame format The frame starts with a start character 0xAA alternating ones and zeros This is followed by the destination address the source address the command code the data count the data a checksum and an end flag 0xFE Start Flag 0XAA Destination Address Source Address Command Data Count Data Checksum End Flag 0XFE Start Flag The star...

Page 19: ...D 0x7F FOR ALL CHARACTERS IN FRAME End Flag A character 0XFE ends the frame Commands Commands from the remote controller to the BM A1 Code Hex Function Reply 80 General prompt for a reply C0 ACK OK C1 NAK send again 81 Use first data char as a second command ACK 82 Request unit identifier C2 83 Set up switches Data count 5 See below for format ACK 84 Set up alarm functions Data count 2 See below f...

Page 20: ...of Right speaker select Right speaker select Ms bit of Left speaker select Left speaker select Byte 2 Ms Red zone Red zone Red zone Red zone Red zone Byte 3 Ms amber zone Amber zone Amber zone Amber zone Amber zone Byte 4 AES offset Ms Peak type Peak type Ms bar type Bar type Bar type Audio select codes Code Function Notes 000 Analog audio input selected 001 AES audio input selected 010 None 011 N...

Page 21: ...d zone data corresponds to the length of the amber zone This zone is attached to the bottom of the red zone Bar type These 3 bits select the bar ballistics and type Code Bar type 000 AES 001 DIN 010 VU 011 BBC 100 Extended VU 101 Nordic Bar peak indicator These two bits select the peak indicator timing Code Time 00 No peak indicator 01 3 Second hold time 10 7 Second hold time 11 Indefinite hold ti...

Page 22: ...f Audio select Audio select Audio select Byte 1 Alarms Audio loss 4 Audio loss 3 Audio loss 2 Audio loss 1 Byte 2 Alarms Anti phase 3 4 Anti phase 1 2 Audio over level 1 Audio over level 1 Audio over level 1 Audio over level 1 Byte 3 AES 2 lock AES 1 lock Byte 4 Byte 5 Armed Audio loss 4 Armed Audio loss 3 Armed Audio loss 2 Armed Audio loss 1 Byte 6 Armed Anti phase 3 4 Armed Anti phase 1 2 Armed...

Page 23: ...rief error information is carried in two data bytes Byte 0 Error message value Byte 1 Erroneous checksum character Error message values Value Message 1 A time out occurred after receipt of a valid start character 2 A character was detected before receipt of a start character 3 A checksum error occurred The erroneous value is placed in Byte 1 RS232 format 8 data bits no parity 2 stop bits 9600 Baud...

Page 24: ...ror between channels 1 and 2 PHASE CH3 4 lights red to indicate a phase error between channels 3 and 4 ON lights green when the unit is powered and switched on LIMIT lights red to indicate that the soft limiter is protecting the speakers AES A lights yellow to indicate the presence of the AES A input AES B lights yellow to indicate the presence of the AES B input ALARM lights yellow to indicate an...

Page 25: ...to sound even though normal signals have been restored Mute the alarm with the ALARM MUTE switch or reset all alarms with the ALARM RESET switch by holding it upwards for more than 3 seconds An input signal has failed but no alarm was asserted Alarms are only generated in respect of selected audio signals when the ALARM SET switch is in the SET position Why can t I enable an audio tone or external...

Page 26: ...t level Noise THD 15dB 95dB Analog input 98dB AES input Frequency response All analog outputs 20 Hz to 20kHz 1dB Main drive amps Noise THD 80dB w r t maximum output Speaker driver units Total peak acoustic level 2ft 100dB SPL Shielding Magnetic Main drive amp Noise THD 80dB w r t maximum output Speaker driver units Peak acoustic level 2ft Shielding 100dB SPL Magnetic Meters Level meters 4 x hi res...

Page 27: ...23dB 3 to 20dB Attack time 300mSec Fallback 300mSec VU EXT Overall dynamic range 80dB 20 to 60dB Attack time 300mSec Fallback 300mSec AES EBU Overall dynamic range 60dB 0 to 60dB Attack time 1mSec Fallback 1 5Sec per 20dB decay Alarms Audio loss audio over level sustained audio anti phase AES EBU carrier loss Housing 19 Rack Mount 1U high Outline Dimensions 483mm W x 283mm D x 44 3mm H 19inch W x ...